This invention will broadly relate to cylinders, and more particularly relate to a swing cylinder especially for holding workpieces.
Swing cylinders and swing clamping devices are well known in the art. Generally, the cylinder is sealed on the end away from the clamping arm with a flange connecting plate, and a swinging guide sleeve for the piston rod, which has a relatively small diameter with respect to the inside diameter of the cylinder. The piston rod is secured only in and on a relatively short bore of the upper cylinder bottom which forms a unit with the cylinder. Apart from the fact that the cylinder is accessible only from its mounting side end, installation or removal of the piston rod with the piston and the guide sleeve are possible only from the mounting side of the cylinder. The swing guide slot for the piston must remain open in order to be able to remove the piston rod from the guide sleeve at all if it is to remain in the cylinder. The guide slot that is open at the end, however is more or less unstable to a certain extent because it can be spread apart more or less conically unless it is over diminished with regard to its wall thickness. Many prior art swing clamping devices also include components that can be inserted into the cylinder from either side. Such components can also be removed from the same sides of the swing cylinder. Many of these prior art swing cylinders rotate to a closed position from an open position in a helical type rotating pattern which allows the swing cylinder to rotate to an open position from a closed position along an angled rotating surface like that of a screw thread.
Many of these prior art swing cylinders may have problems with repeating the exact clamping forces at an exact position due to the play or wobble generally located in the swing cylinder components. Furthermore, many of these prior art swing cylinders cannot hold with a force that the clamp cylinder is capable of producing because of deflection and wobble of internal components of the prior art swing cylinders. The use of a helical rotating swing arm in prior art swing cylinders increases the foot print and area surrounding the swing cylinder necessary to operate in the various manufacturing environments. The increase in foot print and surrounding areas decreases the efficiency of the manufacturing line while increasing the cost by enlarging the space needed to operate the manufacturing line.
Most of the prior art swing cylinders use a guide sleeve arranged around a piston rod which will rotate the piston rod in a generally helical type pattern that rises at a predetermined angle in a constant manner. Therefore, all of the rotating parts around the guide sleeve increases wear and reduces the durability of the swing cylinder clamp in the manufacturing environment. Therefore, there is a need in the art for an improved swing cylinder. There also is a need in the art for an improved swing cylinder that has a smaller foot print. There also is the need in the art for a swing cylinder that operates along two planes only thus reducing the area needed for the swing clamp to operate.
There also is a need in the art for a new swing cylinder that has greater clamping force without increasing the size of the clamp foot print. There also is a need in the art for a clamp that has a predetermined exactness of location repeatability that will allow for a smaller clamp to operate in precise holding situations found in some manufacturing environments.
There also is a need in the art for a swing cylinder that uses an oval bore in a cylinder to increase the strength of the swing clamp and the holding force the swing clamp can apply.